The Cactus Framework is an open source, modular, portable, programming environment for collaborative HPC computing. The Cactus Framework allows large-scale cooperations across the globe, where individual groups design and maintain individual code modules, relying on Cactus to make these modules interoperate. Cactus is nowadays used by more than a dozen research groups worldwide (LSU, AEI, Cardiff, GSFC, MPA, Pittsburgh, PSU, Sissa, Soton, UTB, TAT, Thessaloniki, WashU) to exchange codes and define data formats.
Cactus contains a generic parallel computational toolkit designed for high-performance computing. This toolkit runs efficiently on platforms of all scales, ranging from personal notebooks to the world's larges supercomputers. It provides parallel drivers, coordinates, boundary conditions, time integrators, elliptic solvers (e.g. PETSc), interpolators, reduction operations, and efficient I/O in different data formats (e.g. HDF5). Generic interfaces are used, e.g. an abstract elliptic solver API, making it possible to develop improved modules which are immediately available to the user community.
Simulation data may be analyzed and visualized by a range of external applications, such as Amira, IDL, or OpenDX, and can also be analyzed in-line by use of a web-server module. Cactus is used and developed by numerous application communities internationally, including Numerical Relativity, Climate Modelling, Astrophysics, Biological Computing, and Chemical Engineering. It is a driving framework for a number of computing infrastructure projects, particularly in Grid Computing, such as GridLab, GriKSL, and the Astrophysical Simulation Collaboratory.
The oldest application area of the Cactus framework is numerical relativity. The Einstein equations, which describe how spacetime curves as response to its matter content, are a set of ten coupled nonlinear partial differential equations. Solving these equations requires large computational resources and advanced numerical methods. One current major goal in numerical relativity is the accurate simulation of two orbiting black holes to determine accurately the gravitational radiation that is produced by such a system.
Another major effort at CCT is to establish a CFD toolkit within the Cactus framework, which allows researchers and students to quickly implement their favourite model, being able to experiment e.g. with grid topologies, boundary conditions, and solution methods. The scalable multi-processor parallelism that Cactus has to offer will make possible a more interactive approach to CFD.
Cactus was originally developed at the Max Planck Institute for Gravitational Physics in Potsdam, Germany, with many contributions from colleagues around the world, including Washington University, Lawrence Berkeley National Laboratory, National Center for Supercomputing Applications, and the University of Tübingen. In 2003, much of the Cactus development moved to the Frameworks research group at the CCT. Researchers in Baton Rouge and Potsdam now work closely together to further enhance and support Cactus.
[Adaptive Mesh Refinement] E. Schnetter, S. H. Hawley, I. Hawke, Evolutions in 3D numerical relativity using fixed mesh refinement, Class. Quantum Grav. 21, 1465 (2004), gr-qc/0310042.
[Relativistic Hydrodynamics Toolkit] L. Baiotti, I. Hawke, P. J. Montero, F. Löffler, L. Rezzolla, N. Stergioulas, J. A. Font, E. Seidel, Three-dimensional relativistic simulations of rotating neutron star collapse to a Kerr black hole, Phys. Rev. D 71, 024035 (2005), gr-qc/0403029.
- Dr. Gabrielle Allen (CCT/CS)
- Dr. Edward Seidel (CCT/Physics)
- Tom Goodale (CCT/CS)
- Yaakoub El-Khamra (CCT/CS)
- Maciej Brodowicz (CCT/CS)
- Erik Schnetter (CCT/Physics)
- Sasanka Madiraju
- Dylan Stark
- Josh Abadie
- Jeff DeReus
- Alex Nagelberg
- Rakesh Yadav
For more information about the Cactus Framework at CCT, please contact Dr. Gabrielle Allen